Effects of deuteration on displacive-type ferroelectric phase transition of LiTlC4H4O6.H2O

The effects of deuteration on the ferroelectric phase transition of LiTlC 4 H 4 O 6 ·H 2 O (LTT) have been studied through dielectric measurements. The phase transition temperature T c decreases with increasing concentration of deuterium in the crystal, and vanishes in the highly deuterated crystal. On the other hand, the Curie-Weiss constant C remains almost constant with deuteration. The decreasing and vanishing of T c with a finite C in deuterated LTT is attributed to the phase transition mechanism of displacive-type.